The overall goals of the research are to learn more about the roles of the parallel X, Y, and W pathways in visual system function and development. These goals will be accomplished by studying visual system physiology in normal cats and cats that have been raised in an abnormal visual environment. In addition, we will continue our work to devise procedures to selectively eliminate particular components of the parallel visual pathways. The specific aims of the research are: 1) Investigate the nature of binocular interactions on neurons in the lateral geniculate nucleus (LGN). This will include a quantitative spatial frequency analysis of receptive-field properties through the non-dominant eye and a comparison of these properties for X, Y, and W cells in the LGN. In addition, it will include an analysis of the effects of non-dominant eye stimulation on specific receptive-field properties through the dominant eye. 2) Investigate the effects of early visual experience on the function of the W-cell pathway through the LGN. This will be accomplished by recording from neurons in the C laminae of the LGN in monocularly deprived cats. 3) Continue efforts to develop new and better methods for selectively eliminating retinal X, Y, or W cells and their projections to the brain. Three different approaches will be used to meet this aim. The first will asssess the possibility that monoclonal antibodies can be used, either alone or conjugated to a neurotoxin, to destroy a specific class of retinal ganglion cells. The second will determine whether retrogradely transported neurotoxins can be used to eliminate specific classes of retinal ganglion cells. The third will determine if selective photothermolysis can be used to eliminate specific classes of retinal ganglion cells. This project will help elucidate the brain mechanisms of both normal and abnormal vision.